Pneumatically actuated antioverflow alarm and safety device for tankers



2 l 4 6 .m e, 2 H 7 .7a. WS ma 2@ Fm 5 Rm 5. IR T02 NF5 5 AEN DC SEI9. F EMM?. 7 H .UDY LT a mnu HYmm CDF um 7 mm 5 ma M P F/Qi' May 25, 1954 Patented May 25,rv 1954 PNEUMATICALLY ACTUATED ANTIOVER- FLOW ALARM AND SAFETY DEVICE FOR TANKERS Harry Liles, Yeadon, Pa. Application May 29, 1952, Serial No. 290,699

4 Claims.

This invention relates primarily to a means for avoiding overflow of the individual tanks of oil tanker vessels during the loading operation, and a principal object of the invention is to provide a device of this character comprising a suitable signal or alarm responsive to an abnormally high liquid level in any one of the tanks of the vessel whereby the pumping of the oil to the tanks, or to the particular tank wherein overflow is threatened, may be interrupted in due time.

Another object of the invention is to provide a device of the stated character comprising a fluid system associated with a plurality or all of said tanks and operatively connected with a common alarm or signal device,

A further object is to provide a safety device of the stated character which will function also as a means for signalling the presence in any of the tanks of abnormally high pressures.

Still another object of the invention is to provide a device of the stated character having readily accessible means for checking the operativeness of the elements of the apparatus.

The invention resides also in certain mechanical and structural details, hereinafter described and illustrated in the attached drawings, where- 1n:

Figure 1 is a diagrammatic cross-sectional view of a typical oil tanker;

Figure 2 is an enlarged diagrammatic elevational and partial sectional view illustrating details of the anti-overilow and pressure alarm system shown in Figure l;

Figure 3 is an enlarged sectional view illustrating a detail of the apparatus shown in Figure 2, and

Figure 4 is a diagrammatic sectional view illustrating a modification within the scope of the invention.

Oil tanker vessels are conventionally divided by suitable bulkheads into a number of individual compartments or tanks, and it is customary to provide also a supply pipe system which extends; to all of the individual tanks and through which the tanks may be simultaneously filled with the oil cargo pumped through the system from an external supply source. Each of the tanks is provided with a man-hole at the top by which access may be had to the interior of the tank from the deck of the vessel; and each man-hole cover is usually provided with a small opening having a detachable cover and constituting what is known as a ullage hole through which the interior of the tank may be inspected to determine the level of the oil in that particular tank at any instant. It has been found that the rate of charge in the various tanks, while theoretically the same, is actually subject to relative variation by reason of different local conditions aiiecting the oil flow, so that in loading the level of the oil in one tank cannot be used as an index of the level in the other tanks. In the larger 'tankers particularly, the number of individual tanks is so great that constant inspection of all of the tanks by way 'of the "ullage holes during the filling operation is not feasible, and it frequently occurs that one or more of the tanks will ll to overflow in the interval of time between successive inspections of that tank. Since such overiiowi is highly undesirable by reason of resulting harbor contamination and the very real fire hazard involved in the presence of oil on the deck o f the tanker, it is of importance that overflow be avoided if possible. Such avoidance is the primary object of the present invention.

With reference to the drawings, the numeral l indicates the hull of a typical oil tanker which, in. accordance with the usual practice, contains a series of transverse bulkheads, of which one is indicated at 2, and one or more longitudinal bulkheads indicated in the present instance at 3 and 4 respectively, which bulkheads divide the interior of the vessel into a number of individual tanks for the oil cargo. Each of the tanks is provided at the top with a man-hole 5 and each man-hole cover 6 is provided with an opening normally closed by a detachable cover 1, this hole, known as the knowledge hole, being provided for the purpose of inspection to determine the level of the oil in the tank.

Manifold pipes Il, I2 and I3 extend longitudinally of the vessel through the respective longitudinal rows of tanks, and these pipes conventionally constitute elements of a single system through which oil is pumped from external source to the individual tanks of the vessel. The pipes II, I2 and I3 communicate with the individual tanks by means of branch ducts I4, I 5 and I 6 and each of these ducts contains a valve I l by means of which the duct may be opened or closed, or restricted, as may be found desirable. The valves I'I are actuated manually by way of valve rods I8 which extend upwardly to the top of the tank, the upper ends of the rods being laccessible through independent openings, not shown, in the top wall or deck I9. By this means each of the tanks may be individually connected or disconnected from the oil supply source and the rate of lling may be regulated as may be found desirable.

In accordance with the present invention I provide in the top of each of the tanks an inverted cup or bell, indicated in Figure 1 by the reference numerals 2l, 22 and 23 respectively. A duct 24, 25 and 26 respectively extends from the top of each of these bells to a fitting designated generally by the reference numeral 21 and in the present instance the three fittings associated with the individual tanks 28, 29 and 3l shown in Figure l are mounted in a housing 32 located in a suitable position above the deck i9 externally of the tanks. The fittings 21 are of the form illustrated in Figure 3, wherein it will be noted that the duct 24, in this instance, communicates with a vertical hollow stem 33 having in the upper portion thereof a seat 34 for a spherical check valve 35. This valve is confined in a chamber in the top of the stem 33 by a screw plug 36 which may be removed to afford access to the valve element. The side walls of the valve chamber are provided with ports 31 which when the ball valve 35 is unseated establish communication between the duct 24 and chamber 38 in the interior of the fitting 21. This chamber embraces the stem 33 and access to the chamber and to the stem may be had by removal of a screw cap 39 at the top of the fitting. The chamber 3S has ports at opposite sides and through these ports the chamber of each of the fittings is connected with the chamber of the other fittings of the group by Way of nipples 4I. The port 42 of one of the terminal ttings 21 is provided with a hollow plug 43 containing a valve 44 whereby the chamber 38 may be connected with an external source of air pressure, not shown, or with the atmosphere for purposes hereinafter described. The port 45 ot the fitting 21 at the opposite end of the group is connected by way of a tube 4S with a Sylphon bellows 41. This bellows is connected to a lever 48 pivoted at 49 and operatively connected at its opposite end, by way of an adjustable pin I, with the actuating element of a suitable switch 52. This switch controls and electric circuit 53 containing an electric alarm or signal bell 54.

In the operation of this device it will be apparent that when the level of oil in the tanks, or in any one of the tanks, reaches the bottom of the associated bell, 2|, 22 or 23 as the case may be, the continued flow of oil into the tank r will place the air trapped within the bell under a continuously increasing pressure. This pressure elevates the ball valve 35 of the associated fitting 21 and permits displacement of air from the bell through the ports 31, the chamber 38, and the tube 46 to the bellows 41. This results in an immediate expansion of the bellows and a tripping of the switch 52 with resultant sounding of the alarm. The entire loading operation may then be interrupted or, if the critical tank has been located, that tank may be disconnected from the supply source by closure of the associated valve I1. The extra air in the system which caused the expansion ofthe Sylphon 41 may then be exhausted by opening of the valve 44 to bleed the system, thereby returning the Sylphon 41 to its original position and placing the system in condition for subsequent operation in the event that another of the tanks becomes full before the others.

It will be noted that by reason of the location of the bells 2 l, 22 and 23 in the upper portions of the tank, the device is normally unaffected until the liquid level in one or more of the tanks has risen to an abnormal position,

it being understood that each of the tanks is vented at the top so as to permit escape of air from the upper areas of the tank to the atmosphere as the air is displaced by the oil entering the tank. The device is highly sensitive in that it operates almost immediately after the level of the liquid has covered the open bottom of the bell.

The device is also operative to sound the ala-rm 54 in event of clogging of the vent in any of the tanks and the resulting increase in the pressure within the tank due to the injected oil. This is an important phase of the invention in that it prevents development of dangerous pressures in the individual tanks which might under certain conditions cause rupture of a bulkhead.

The device described above provides also for a thorough check of the anti-overflow system to give assurance that all parts of the system are in proper functioning condition. Each of the check valves 35 may be inspected by removal of the cap 39 of the associated fitting 21 and of the plug 36. By removal of the valve 35 compressed air may be injected through the stem 33 and duct 24 to make sure that the passages are clear and unobstructed. After replacement of the valve and of the cap 39 application of pressure air to the system may be effected by way of the tting 43, and if the several valves are in order the resulting elevation of pressure in the system will sound the alarm and thereby indicate that the system is in proper working condition.

For the purpose of simplification, I have described the invention in terms of the three tanks of a transverse group. It will be understood, however, that the invention contemplates the inclusion of all the tanks in a common system and this is accomplished in the present instance by connecting each of the transverse groups of tanks with the other transverse groups through a manifold 55 which extends the full length of the vessel and which is connected with the common alarm which includes the Sylphon 41 and bell 54. The switch 52 may be of any desired type of adequate sensitiveness, but a switch of the mercury bulb type is desirable by reason of its non-sparking characteristic.

In the aforedescribed embodiment of my invention the check valves 35 associated with the respective tanks are essential in order that the air displaced by the rising oil in one or more of the bells will pass to the Sylphon 41 instead of back into the bells of the other tanks. In Figure 4 I have illustrated a system by which the valves may be eliminated. In this case, each of the bells is provided at the top with an imperforate iiexible diaphragm 56 which is backed on the underside in the present instance by a perforated plate 51. The diaphragm forms a chamber 58 in the extreme top of the bell which is separated from the main chamber of the bell below the plate 51. The chamber 58 is connected through a suitable duct 59 with a Sylphon 6I which lis associated with a suitable signal or alarm of the character previously described and illustrated in Figure 2 of the drawings. The Sylphon El and the pipe system connecting this Sylphon with the chamber 58 of the bell, and the chamber 58 itself, is lled with a suitable liquid so that any increase in air pressure in the lower portion of the bell resulting from the rising oil level will result in an upward displacement of the diaphragm 56 and a displacement of the liquid from the chamber 58 to the Sylphon 6|, thus sounding the alarm. Each of the bells of the several tanks will be similarly connected by a common liquid system to the Sylphon 6| in obvious manner, it being apparent that the displacement of liquid resulting from the elevation of one of the diaphragms 56 must manifest itself in an expansion of the Sylphon 6| by reason of the support of the diaphragms of the other bells by the associated perforated plates 5l. While this embodiment of the device is relatively simple by reason of its elimination of the valves 35 of the other embodiments, it does not lend itself as readily to check for operativeness. It will be apparent, however, that means can readily be provided for insuring that the system is in operative condition.

While having an application of particular value to oil tank vessels as described above, the invention is applicable also to oil storage tanks wherein it may be usefully employed to provide warning against overflow and lagainst development Within one or a number of tanks of excessive pressures, all in accordance with the previously described principle.

I claim:

1. In an anti-overilow device for the several tanks of an oil tank vessel, an inverted cup in each or said tanks located so that its lower edge adjoins the normal upper level of oil in the tank, a pneumatic system connected with the upper ends of all of said cups and including a displaceable element responsive to abnormal pressure within said system, signal means operatively connected to said element, and a check valve controlling the connection between each of said cups and said system, said valves permitting displacement of air from the cups to the system but precluding a displacement in the opposite direction.

2. An anti-overow device according to claim 1 whereinthe said check valves are located so as to be accessible from the exteriors of the tank.

3. An anti-overow device according to claim 2 wherein the said check valve comprises a casing having a releasable access opening providing for inspection of the valve structure.

4. An anti-overflow device according to claim 3 wherein the system comprises a port intermediate the said valves and the displaceable element and releasable means for normally sealing said port, said port affording access to the system for application to the latter of pressure uid and for bleeding the system of excess air pressure.

References Cited in the flle 0f this patent UNITED STATES PATENTS Number Name Date 867,994 Murphy Oct. 15, 1907 987,518 Wendling Mar. 21, 1911 1,055,099 Sullivan Mar. 4, 1913 2,058,061 Clinch Oct. 20, 1936 2,334,220 Samiran Nov. 16, 1943 2,378,135 Evans June 12, 1945 2,547,526 Hilliard Apr. 3, 1951 FOREIGN PATENTS Number Country Date 304,087 Italy Dec. 14, 1932 

